[Bug c/110654] inconsistent error message in presence of unexpected encoded characters

[pinskia at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=110654

--- Comment #1 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
libccp has:
          /* In C++, this is an error for invalid character in an identifier
             because logically, the UTF-8 was converted to a UCN during
             translation phase 1 (even though we don't physically do it that
             way).  In C, this byte rather becomes grammatically a separate
             token.  */

          if (CPP_OPTION (pfile, cplusplus))
            cpp_error (pfile, CPP_DL_ERROR,
                       "extended character %.*s is not valid in an identifier",
                       (int) (*pstr - base), base);
          else
            {
              *pstr = base;
              return false;
            }


So this is due to differences in the languages themselves rather than due to C
vs C++ front-end ...